GPS开发常用方法 和用Criteria确定android location providerGPS开发常用方法

GPS常用方法总结

取得LocationProvider

public void getLocationProvider() { try { Criteria mCriteria01 = new Criteria(); mCriteria01.setAccuracy(Criteria.ACCURACY_FINE); mCriteria01.setAltitudeRequired(false); mCriteria01.setBearingRequired(false); mCriteria01.setCostAllowed(true); mCriteria01.setPowerRequirement(Criteria.POWER_LOW); strLocationProvider = mLocationManager01.getBestProvider(mCriteria01, true); mLocation01 = mLocationManager01.getLastKnownLocation (strLocationProvider); } catch(Exception e) { mTextView01.setText(e.toString()); e.printStackTrace(); } }

获取经纬度，并返回GeoPoint对象

private GeoPoint getGeoByLocation(Location location) { GeoPoint gp = null; try { if (location != null) { double geoLatitude = location.getLatitude()*1E6; double geoLongitude = location.getLongitude()*1E6; gp = new GeoPoint((int) geoLatitude, (int) geoLongitude); } } catch(Exception e) { e.printStackTrace(); } return gp; }

将经纬度转换成实际屏幕坐标

Point myScreenCoords = new Point(); GeoPoint tmpGeoPoint = new GeoPoint((int)(mLocation.getLatitude()*1E6),(int)(mLocation.getLongitude()*1E6)); mapView.getProjection().toPixels(tmpGeoPoint, myScreenCoords);

点击MapView任意一点获得坐标

@Override public boolean onTouchEvent(MotionEvent ev) { int actionType = ev.getAction(); switch (actionType) { case MotionEvent.ACTION_UP: Projection proj = mapView.getProjection(); GeoPoint loc = proj.fromPixels((int)arg0.getX(), (int)arg0.getY()); String sirina=Double.toString(loc.getLongitudeE6()/1000000); String dolzina=Double.toString(loc.getLatitudeE6()/1000000); } return false; }

经纬度改变来刷新地图

 public void refreshMapView() { GeoPoint p = new GeoPoint((int)(dLat* 1E6), (int)(dLng* 1E6)); mMapView01.displayZoomControls(true); mMapController01.animateTo(p); mMapController01.setZoom(intZoomLevel); }

根据当前的经纬度，获取相关的一些地址信息

 //根据地理环境来确定编码 //注意这个Locale是java.util.Locale包的类,获取当前系统设定的语言 Geocoder gc = new Geocoder (EX09_05.this, Locale.getDefault()); double geoLatitude = (int)gp.getLatitudeE6()/1E6; double geoLongitude = (int)gp.getLongitudeE6()/1E6; List<Address> lstAddress = gc.getFromLocation(geoLatitude, geoLongitude, 1); StringBuilder sb = new StringBuilder(); if (lstAddress.size() > 0) { Address adsLocation = lstAddress.get(0); for(int i=0;i<adsLocation.getMaxAddressLineIndex();i++) { sb.append(adsLocation.getAddressLine(i)).append("\n"); } sb.append(adsLocation.getLocality()).append("\n"); sb.append(adsLocation.getPostalCode()).append("\n"); sb.append(adsLocation.getCountryName()); }

根据输入地址，取得其GeoPoint对象

 private GeoPoint getGeoByAddress(String strSearchAddress) { GeoPoint gp = null; try { if(strSearchAddress!="") { Geocoder mGeocoder01 = new Geocoder (EX09_07.this, Locale.getDefault()); List<Address> lstAddress = mGeocoder01.getFromLocationName (strSearchAddress, 1); if (!lstAddress.isEmpty()) { Address adsLocation = lstAddress.get(0); double geoLatitude = adsLocation.getLatitude()*1E6; double geoLongitude = adsLocation.getLongitude()*1E6; gp = new GeoPoint((int) geoLatitude, (int) geoLongitude); } } } catch (Exception e) { e.printStackTrace(); } return gp; }

地图放大缩小按钮

 mButton02 = (Button)findViewById(R.id.myButton2); mButton02.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { intZoomLevel++; if(intZoomLevel>mMapView01.getMaxZoomLevel()) { intZoomLevel = mMapView01.getMaxZoomLevel(); } mMapController01.setZoom(intZoomLevel); } }); mButton03 = (Button)findViewById(R.id.myButton3); mButton03.setOnClickListener(new Button.OnClickListener() { public void onClick(View v) { intZoomLevel--; if(intZoomLevel<1) { intZoomLevel = 1; } mMapController01.setZoom(intZoomLevel); } });

以下文章转载： http://marshal.easymorse.com/archives/2528
android location provider有两个：

* LocationManager.GPS_PROVIDER：GPS，精度比较高，但是慢而且消耗电力，而且可能因为天气原因或者障碍物而无法获取卫星信息，另外设备可能没有GPS模块；
* LocationManager.NETWORK_PROVIDER：通过网络获取定位信息，精度低，耗电少，获取信息速度较快，不依赖GPS模块。

为了程序的通用性，希望动态选择location provider。对android通过Location API显示地址信息做了个别改动，可以看到使用了gps定位，精度较高：



这里使用到了Criteria，可根据当前设备情况自动选择哪种location provider。见

LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); Criteria criteria = new Criteria(); criteria.setAccuracy(Criteria.ACCURACY_FINE);// 设置为最大精度 criteria.setAltitudeRequired(false);//不要求海拔信息 criteria.setBearingRequired(false);// 不要求方位信息 criteria.setCostAllowed(true);//是否允许付费 criteria.setPowerRequirement(Criteria.POWER_LOW);// 对电量的要求 location = locationManager .getLastKnownLocation(locationManager.getBestProvider(criteria, true));

原来的写法很简单：